Encore CS5 DVD subtitles not appearing in Windows Media Player

I have a DVD that I have authored using Adobe Encore CS5, and added several subtitle tracks (English, French, Spanish, Chinese) for required Section 508 compliance. After burning the DVD, everything works fine on your standard DVD player hooked up to a TV. The same is true for Windows Media Player on Win7 and Nero Showtime on Win7 and XP.

The problem is when you try to play the DVD on an XP system using Windows Media player, (v. 10 and 11 tested) none of the captions are displayed. In the player’s settings, the captions are turned on, and you can even navigate and see where whatever language you selected is in fact, selected. In the WMP window, you can see the area where there is the extra black space for the captions to display, but they’re just not there.

That's good to know, but I assumed that was the case since it works on consumer DVD players, Nero, and Win 7. Not so good since my boss is still looking at me and asking why the captions aren't showing up on his computer.

Lemme know if you can find anything else. I scoured the Microsoft website, and all I found was the standard instructions for displaying captions.

Windows Media Player 11 offers enhanced security features on the Security tab of the Options dialog box:

Show local captions when present. Windows Media Player supports Synchronized Accessible Media Interchange (SAMI) captioning of media content. SAMI content can be located on the Internet, your hard disk, or your CD or DVD. During playback, Windows Media Player accesses the content to locate and display SAMI captions. Enabling this option allows access to SAMI content in all of the content zones available to your computer. Clearing this option will limit access to the Internet zone. This option is turned off by default.

From what I've read in the Adobe Encore CS5 help manual, Encore does not allow for the importation of SAMI (SMI) files. Is that correct? All it appears to allow for import are text scripts (.txt) and FAB/Image Scripts.

I've used SAMI when using WMP embedded on web pages, but this is a DVD.